Picking up and laying down drill pipe casing and other tubular goods in the drilling of oil and gas wells requires extreme caution both to protect the personnel on the rig and also to protect the pipe threads from damage. As the projected depth of the wells being drilled increases, the height of the rig floor increases to accommodate additional blowout preventers and other equipment required. To accommodate picking up and laying down pipe, particularly on these higher rig floors, larger and more sophisticated pick up and laydown equipment is required to handle the greater heights and the steeper angles of approach from the catwalk to the rig floor. If the angle of approach is too steep, the upper end of the joint of pipe will be too high above the rig floor for a worker standing on the floor to safely reach and therefore means are required to raise the rear end of the pickup line to lower the angle of approach to the elevated rig floor and also to lower the upper end of the pipe with respect to the rig floor. A number of the prior art pick up and laydown machines have a fixed angle of approach and are exemplified by U.S. Pat. Nos. 4,054,210; 4,099,630 and 4,082,193. Many of these devices must be positioned immediately adjacent and anchored or secured to the catwalk or some other support structure to resist an overturning moment or movement horizontally.
On many locations the controls for the operation of the blowout preventers or other equipment are positioned at the outer end of the catwalk where pick up and laydown machines are normally positioned and therefore the catwalk cannot be used to stabilize the pickup and laydown machine and provide the means for resisting tipping of the pick up unit under load.